Mercury vapor heating apparatus



Jan. 15, 1935. 1

F. SHORT 1,987,715

MERCURY VAPOR HEATING APPARATUS Original Filed Sept. 2, 1924 2 Sheets-Sheet l fir) ATTORNEY A Jan. 15, 1935. 5 SHORT MERCURY VAPOR HEATING APPARATUS Original Filed Sept. 2, 1924 2 Sheets-Sheet 2 INVENTOR 17w Jh'ori. BY

ATTORNEY 1 tion of certain of the mercury vapor boilers dis-- Patented Jan. 15, 1935 MERCURY VAPOR HEATING APPARATUS Frank Short, Poughkeepsie, N. Y., assignor to Chemical Machinery Corporation, a corpora- .tion of New York Original application September 2, 1924, SerialNo. 735,495. Divided and this application July 11, 1928, Serial No. 291,907

23'Claims. (Cl. 122-305) This application is. a division of my prior application Ser. No. 735,495, filed September 2nd,

1924, issued Sept. 4, 1928 as patent No. 1,683,310

and is concerned particularly with the construcclosed in said prior application.

These boilers were primarily devised for use in-a closed mercury vapor heating system, which system is maintained at sub-atmospheric pressure throughout, but it will be obvious that they are capable of use in other mercury vapor systems.

A prime desideratum in. such system is to prevent out-leakage of mercury when the internal pressure is above atmosphere endin -leakage of air when the pressure is below atmospheric, and to prevent such leakages one feature of my invention concerns having the couplings between the boilers and the connective pipe lines of the system made within the boiler, so that the possibility of leakage at these points is eliminated. Loosening of connections caused by expansion of the metal parts under the heat to which they are subjected, cannot do any harm when the connections are inside the boiler.

Another object of the invention is to provide a boiler which assures maximum heat generating efliciency while requiring but an inconsiderable quantity of mercury in the system.

Another object is to provide a boiler in which all welded joints or the like are kept from the direct action of the flame, preferably by maintaining them in a mercury bath so that the possibility of difiiculties incidental to heat expansion is further lessened.

Another object is to provide a mercury boiler in which eflicient means is used to prevent entrained liquid mercury from being. carried along to other parts of the system by the vapor which leaves the boiler, said means being preferably a simple form of deflector or baffle impartinga sharp change of direction to the vapor stream before it leaves the boiler and causing it to shed entrained liquid particles.

Other and more general objects of the inven tion are to provide a boiler of the character noted above which will be simple and practical in construction, rugged anddurable in use and well suited to the requirements of economical manufacture and operation.

With the above noted and other objects in view,

the invention consists in certain novel features of construction and combinations and arrangements of parts which will be more fully hereinafter described and pointed out in the claims.

The invention may be more fully understood from the following description in connection with the accompanying drawings, wherein Fig. 1 is a vertical sectional view on the line l-1 of Fig. 2 of a flame. heated mercury vapor boiler embodying the invention;

.Fig.'1a. is an enlarged view of a detail shown in Fig. 1;

Fig. 2 is a sectional viewin the staggered line 2-2 of Fig. 1; Y

Fig. 3 is a view similar toFig. 1 but illustrates a modified form of the invention in which the boiler is inductively heated, and

Fig. 4 is a detail view showing the height of the ferrous cylinders of Fig. 3 as progressively de-- creasing toward the center.

With the form of the invention illustrated in Figs. 1 and 2 of the drawings, the pot 15b for the mercury is provided with the usual flange 63 cooperating with a flange 64 of the cover 65 and thetwo flanges carry the interfitting cylindrical partitions 66-which form the labyrinth of the mercury seal, described at some length in the parent application above referred to. The outer trough of the seal is encircled by a cooling jacket 60 provided-with an inlet 61 and outlet 62 for the admission and-discharge of air or other suitable cooling fluid.

The pot is comparatively shallow and preferably'includes a flat bottom 67 from which depend a numberoi flame heated tubes 68. These tubes are welded to the pot as indicated'at 69 and further anchored by the non-conductin cement '70 which protects the pot from the direct heat of the flame. An outlet pipe 71 for the mercury vapor is welded to the pot above the mercury level therein and the inlet for return mercury includes a pipe 72 entering a pocket 73 in the wall of the pot and coupled at 74 within the pot to a discharge nozzle '75 which delivers mercury below the liquid level. Extending downwardly into each flame heated tube 68 and terminating just short of the bottom thereof is a feed tube 76 of relatively small diameter opening at its upper end into a-distributing groove '77 which forms one of a connected series of grooves in a baiile plate78 extending across the pot just above the liquid level therein. The general double H-shaped arrangement of connected grooves in the baffle plate may be seen in Fig. 2, but is of course subject to wide variation.

Any appropriate number of the flame heated tubes 68 may be used and preferably inlet nozzle '75 discharges downwardly into one of the distributing grooves. Encircling the small down flow feed tubes are cylindrical recirculation tubes 79 carrying feet for limiting their downward movement. Upward floating movement of the cylindrical members 79 is limited by radially projecting lugs 81 on the upper ends of the feed tubes. The circulation of mercury is down through the feed tubes 76 and up through the space between the boiler tubes 68 and floating tubes '79, the floating recirculation tubes providing a path for further downward flow of mercury when necessary. The vapor escapes around the edges of the bafiie plate, such plate being held down by a series of spaced lugs, 83 projecting downwardly from the cover 65. The loose tubes 79 tend to float upward against the lugs 81, thus adding to buoyancy effect of the tubes 76, whereby the baffie plate '78 is forced upwardly toward the limiting stops 83. This permits a certain amount of rise and fall of the bafile plate between an upper position, where tubes 79 contact with lugs 81 and bafile plate 78 is thrust against lugs 83, and a lower position where tube 79 is supported by lugs 80 and its upper end, supports baifle plate '78, through lugs 81. Thus these parts are automatically maintained in desirable operating relation without the necessity of any welding or otherwise positive securing of any of these elements to the exterior shell of the boiler. Consequently, expansion and contraction strains are avoided and the parts are readily removable for cleaning, repair or replacement. The boiler tubes preferably have their bottom ends drawn so that there will be no need to Weld any part which comes directly in contact with the flames. The thickness of the three sets of tubes is so proportioned that a minimum of mercury is allowed for proper functioning of the boiler.

The flame heated boiler has a certain advantage over electrically heated devices in that it uses a less costly fuel. All of the welds are kept from the direct action of the flame (mainly bathed in mercury) and heat expansion cannot cause difficulty with the tubes.

In this arrangement, it will be noted that the relatively cold condensate returning through conduit '72, is discharged through nozzle '75 into grooves '77 of baflle plate 78. This keeps the relatively cold mercury separate from the boiling mercury which is giving off vapor to the offtake 71. From the groove 77, this condensed mercury flows downward through the conduit 76 to the hot low level portions of the boiler, there being in the present case a plurality of these hot portions 68. There is further provision for recirculation of the boiling hot part of the mercury, from the top to the bottom of the boiler, through the submerged upper end of tube '79 and through the space between it and the inner tube 76. This downflow recirculation from the top to bottom of the main body of the mercury is of course independent of the downflow 76, and is caused by the heating and boiling of the mercury in the interspace between the exterior of tube '79 and the interior surface of the boiler at 68.

In Fig. 3, I have illustrated a modified type of inductively heated mercury vapor boiler but the guiding of the initial downflow of the cold condensate, in combination with the top-to-bottom recirculation of the boiling part of the mercury, is generically the same as that above described in connection with Fig. 1, although in this Fig. 3, the jet action of the cold condensate has an added function, as will be described below. In this instance, I employ a pot 15a and cover 17a having a flange 34, the pot having an external flange 35' extending below the cover flange and carrying upwardly extending cylindrical partitions 35a which mate with similar depending partitions 34a on the cover flange 34 and cooperatively form the seal. The cover flange and body flange may be provided with a number of radially disposed air cooled fins 39 for maintaining the mercury in the seal below boiling point. Cover and pot are coated with suitable heat insulating material 40 and the boiler is inductively heated by the use of a plurality of flat encircling coils 41. The vapor take off pipe 42 opens into an offset or pocket 43 in the upper end of the pot and liquid mercury is prevented from escaping through the offset by a deflector 24a. The mercury return pipe 45 leads into a pocket or offset 46 approximately diametrically opposite to the vapor take off and couples at 4'7 with an angular discharge pipe 48 terminating in a downwardly directed discharge nozzle 49 which is located below the level of the mercury in the boiler, such level indicated in dotted lines.

A series of concentric cylindrical iron tubes 50, 51, 52 and53, are disposed coaxially with the shell 15a and may conveniently rest upon and be secured to a spider comprising transverse supporting bars 54 which are supported on the rounded bottom of the drum. These tubes are preferably formed with vertical fins or flutes 55 to increase their heat transmitting surface, and in some instances these flutes may touch the inner surface of the next larger cylinder. The top and bottom edges of the cylinders are preferably rounded as indicated at 56, to oifer a minimum resistance to the flow of mercury and the cylinders may progressively decrease in height from the outer to the inner one in order to facilitate the recirculation of mercury down the central tube 50. In connection with such circulation, it may be noted that the jet action of the discharge nozzle will assist the normal convection flow. If at any time, a vacuum should occur in the pipe 45 the immersed nozzle 49 will permit a static column of mercury to be built up, thereby automatically increasing the pressure of the inflow as the internal pressure increases. Since the union 4'7 of this pipe and the nozzle is within the boiler, leakage at the union becomes of no importance. In connection with the deflectors 24a, it may be noted that liquid mercury particles entrained in the vapor and passing along the deflector are subject to a sudden change of direction at the edge of the deflector, which will result in their being dropped by the vapor and returned to the main body of mercury.

It will be noted that in both forms of the boiler, the covers are not only readily removable because of the barometric liquid seal, but further they are of extremely large area, preferably the same or nearly the same as the cross-sectional area. of the boiler, but in any event suflicient so that when they are removed. the condensate return pipes can be readily unscrewed and all of the circulation controlling tubes removed through the top. Thus. when the cover members are removed, all of the interior parts are readily accessible for inspection, removal, cleaning or repair.

I claim:

1. A mercury boiler including a vessel providing a chamber, a liquid inlet and a vapor offtake for the chamber, means for inductively heating mercury in the chamber, and a plurality of concentric cylinders disposed axially of the chamber and providing vertical annular paths for the circulation of mercury.

'2. A mercury boiler including a vessel providinga chamber, a vapor ofltake, a pocket in the wall of the chamber, a liquid inlet including apipe extending into the pocket, a nozzle coupled to the pipe within the chamber and discharging below the liquid level in the chamber whereby incoming mercury agitates the mercury in the chamber.

3. A mercury boiler including a vessel providing a chamber, a heating coilencircling the same, a plurality of connected concentric ferrous cylinders" disposed centrally of the chamber, and supported above the bottom thereof.

4. A'mercury boiler including a vessel providing a chamber, a heating coil encircling the same, a plurality of concentric iron cylinders secured together, disposed centrally of the chamber, and above the bottom thereof, said cylinders being fluted to promote heat transfer;

5. A mercury boiler including a vessel providing a chamber, a. heating coil encircling the same,

a plurality of spaced concentric connected fer-- rous cylinders disposed centrally of thechamber, and supported above the bottom thereof, said cylinders including rounded edges to assist in the free circulation of mercury.

a plurality of concentricferrous cylinders dis' posed'centrally of the chamber, and means disposed above the bottom of the chamber for scouring the cylinders together.

'7. A mercury boiler including a vessel providing a chamber, a heating coil encircling the same, a plurality of concentric ferrous cylinders disposed centrally of the chamber above the bottom thereof, said cylinders being of progressively decreasing height toward the center of the chamber.

8. A mercury boiler including a vessel providing a chamber, a heating coil encircling the same, a plurality of concentric ferrous cylinders disposed centrally of the chamber above the bottom thereof and means for introducing liquid mercury into the chamber including a nozzle discharging below the level of mercury and within the central cylinder.

9. A mercury boiler including a vessel providing a chamber, a plurality of tubes depending from the bottom of the chamber, an unattached baflie plate in the chamber, a plurality of feed tubes depending from the baffle plate into the tubes and means for feeding cool liquid mercury onto the baffle plate.

10. A mercury boiler including a vessel providing a chamber, a plurality of flame heated tubes depending from the bottom of the chamber, a baffle plate free i or movement within the chamber, a plurality of feed tubes depending from the baffle plate, into the flame heated tubes, and means for feeding mercury condensate onto the baiile plate.

11. A mercury boiler including a vessel providing a chamber, a plurality of flame heated tubes depending from the chamber, a bafile plate above the mercury level in the chamber and having communicating distributing grooves therein into which liquid mercury is delivered and feed tubes opening into the distributing grooves and depending into the flame heated tubes.

12. A mercury boiler including a vessel providing a chamber, a plurality of flame heated tubes depending from the chamber, a baffle plate above the mercury level in the chamber and having communicating distributing grooves therein into which liquid mercury is delivered, feed tubes opening into the distributing grooves and depending into the flame heated tubes, and recirculation tubes encircling the feed tubes within the flame heated tubes and connecting upper and lower regions of the boiling mercury, below the level of the surface thereof.

13. A mercury vapor boiler including a vessel, a'plurality of externally heated tubes depending from the vessel, a'bafile plate, above-the mercury level, feed tubes arranged to guide 'downflow of condensate within the externally heated tubes and recirculation tubes encircling the feed tubes and connecting upper and lower regions of the mercury below the level of the surface thereof. 14. A mercury boiler including a vessel providing a chamber, a plurality of flame heated tubes depending from the chambenia bafile plate above the mercury level in the chamber, and having communicating distributing grooves therein into which liquid mercury is delivered, feed tubes opening into the distributing grooves and depending into the flame heated tubes, recirculation tubes encircling the feed tubes within thev flame heated tubes, and means'for limiting the upward movement of the recirculation tubes.

15. A mercury'boiler including a vessel providing-a chamber, a plurality of flame heated tubes depending from the chamber, axially disposed feed tubes within the .flame heated tubes and recirculation tubes between the feed tubes and the flame heated tubes and connecting upper and lower regions of the mercury below the level of the surface thereof.

16. A mercury boiler including a vessel providing a chamber, a plurality of flame heated tubes depending from the chamber, axially disposed feed tubes within the flame heated tubes and recirculation tubes within the flame heated tubes and disposed co-axially therewith and connecting upper and lower regions of the mercury below the level of the surface thereof.

1'7. A mercury boiler including a pot, depending flame heated boiler tubes welded to the pot, a feed tube disposed centrally in each boiler tube and a baffie plate carrying the feed tubes and formed with liquid distributing depressions discharging into said feed tubes.

18. A mercury boiler including a pot, depending flame heated boiler tubes welded to the pot, a feed tube disposed centrally in each boiler tube, an unattached baflle plate carrying the feed tubes, and lugs on the pot cover limiting the floating movement of the baffle plate.

19. A mercury boiler including a pot, flame heated boiler tubes depending from the pot bottom, feed tubes disposed centrally within the boiler tubes, a baflle plate carrying the feed tubes and being of slightly less area than the crosssectional area of the pot whereby to permit the escape of vapor upwardly past the baflle plate, a vapor take-off above the bafile plate and a supply line including a nozzle discharging onto the baffle plate. I

20. A mercury boiler including a pot, flame heated boiler tubes depending from the pot bottom, feed tubes disposed within the boiler tubes, 2. bafile plate carrying the feed tubes and being of slightly less area than the cross-sectional area of the pot whereby to permit the escape of vapor upwardly around the edges of the baflie plate, a vapor take-off above the baflle plate, an inlet including a nozzle discharging onto the baffle plate, and said bafile plate having a plurality of connected distributing grooves in its surface for delivering mercury to the feed tubes, and recirculation tubes between the feed tubes and the flame heater boiler tubes.

21. A mercury boiler comprising anupright pot or body portion containing removable tubular members spaced apart to afford a central path for down circulation of cool mercury condensate to the lower portion of the boiler and other paths for separate up and down thermocirculation of the boiling mercury, said body portion having welded. to the walls thereof a condensate return pipe having an interior removable extension projecting laterally toward the center of the boiler, to discharge the condensate at the center of down flow circulation, in combination with a cover for the boiler with an intermediate barometric mercury seal to prevent outward leakage of mercury'vapor and inward leakage of air under conditions of use; said parts being shaped and proportioned so that removal of the cover uncovers a cross-section ofthe body portion of suificient area to permit detaching of the condensate extension and removal of the circulation determining tubes for cleansing, repair or renewal of the parts.

22. A mercury boiler, including a pot, flame heated boiler tubes depending from the pot botton, feed tubes disposed within the vboiler tubes, a baflle plate carrying the feed tubes and being of slightly less area than the cross sectional area of the pot whereby to permit the escape of vapor upwardly around the edges of the baflle plate, and a vapor take-01f above the baflle plate, in

combination with a cover for the pot with barometric mercury seal to prevent outward leakage of mercury vapor and inward leakage of air under the conditions of use; said parts being shaped and proportioned so that removal of the cover uncovers a cross section of the body portion of suflicient area to permit removal of the baffle plate with the feed tubes carried thereby, for cleansing, repair or renewal of the parts.

23. A mercury boiler, means for heating and vaporizing'low level portions of the mercury in said boiler and conduits for offtake of the vapor and for return of the condensed liquid through high level portions of the walls of said boiler, in combination with means for controlling circulation of the liquid, said means including inner and outer tubular elements, spaced apart and spaced from the boiler wall so as to afford at least three adjacent conduits for flow of mercury between high level and low level regions in said boiler; the interior of the innermost tubular element being arranged to receive the cool condensate from the condensate return conduit and to guide downfiow thereof to a low level region of the liquid; and the outermost of said tubular elements having its open top submerged beneath the surface of said body of mercury, so that the interior thereof constitutes a downfiow conduit, and the space between it and the boiler wall an upflow conduit for recirculation of hot or boiling mercury.

FRANK SHORT. 

